Facile fabrication of Cu single atoms by utilizing nano-constrained environment

Single-atom catalysts (SACs) exhibit exceptional catalytic activity across various processes due to their optimal utilization of metal sites at the atomic level. However, how to produce the SACs simply and efficiently remains a major challenge. Here, we present a convenient method for creating SACs by utilizing the nano-constrained environment between the silica walls and template in template-occupied mesoporous silica KIT-6 (TOK). Following the introduction of Cu precursors to the nano-constrained environment of the TOK via grinding, Cu SACs can be efficiently generated during the calcination process. Individual Cu atoms form a covalent Cu-O-Si structure in the TOK, as evidenced by density functional theory (DFT) simulations and empirical data. In the CO 2 cycloaddition of epichlorohydrin, the yield over CuTOK was 91.7%, which was significantly higher than that of the copper catalysts synthesized without a nano-constrained environment (58.3%). In addition, the turnover frequency (TOF) over CuTOK was 127.3 h -1 , which was much higher than the TOF over various copper-containing catalysts. • The fabrication of Cu single atoms was achieved by utilizing the nano-constrained environment between the template and the silica walls in template-mesoporous silica KIT-6 (TOK). • Cu precursors can readily be introduced to the nano-constrained environment by grinding, and single atoms are constructed in the form of Cu-O-Si during subsequent calcination. • CuTOK shows high activity toward the CO 2 cycloaddition of epichlorohydrin, compared with the catalyst synthesized without the nano-constrained environment and the reported copper-containing catalysts.